[Snippet] [Fix] Added a bash snippet (#219)

* removed bash icon

* fix comments of a script

* added kill_prev snippet

* followed guidelines

Author: saminjay

public/icons/bash.svg

@@ -0,0 +1,20 @@
+---
+title: Kill Previous Instances
+description: Kill all previous instances of a script
+author: saminjay
+tags: kill,process,background
+---
+
+```bash
+function kill_prev() {
+    # $$ contains current pid (grep ignore so it doesn't suicide)
+    local processes
+    readarray -t processes < <(pgrep -f "$0" | grep -v "$$")
+    kill "${processes[@]}" >/dev/null 2>&1
+}
+
+# Usage:
+# Add this function to your background running script
+# It will make sure that only one instance of your script is running at a time
+kill_prev
+```

snippets/bash/system/kill-previous-instances.md

@@ -15,8 +15,8 @@ system_resources () {
 
 system_resources "$@"
 
-// Usage:
-chmod a+x system-resource-monitor.sh // First make it executable for all the users
+# Usage:
+chmod a+x system-resource-monitor.sh # First make it executable for all the users
 
-./system-resource-monitor.sh  // It will print the following system resources (CPU, RAM, disk, and active users)
+./system-resource-monitor.sh  # It will print the following system resources (CPU, RAM, disk, and active users)
 ```